Rotary pump



July l0, 1945. c. w. VAN RANST 2,380,283

7 -ROTARY PUMP Filed March 13, 1942 INVENTOR aw/W ATTORNEYS (yr/ :22:15! Z)? 41156: n

\ Patented July 10, 1945 UNITED STATES PATENT OFFICE ROTARY PUMP Cornelius W. Van Ranst, DearborniMieh.

Application March 13, 1942, Serial No. 434,527

2 Claims. (01. los -132) The present invention relates to new and useful improvements in self-priming rotary pumps adapted for unsu-bmerged operation. In a particular embodiment of the invention described: in detail hereinafter, adapted forpumping liquid fuel to the carburetor of an internal combustion engine. However, the present improvements may be embodied in rotary pumps adapted to operate under other circumstancesand for other purposes.

It is an object of the present invention to provide a rotary pump of novel and simplified desi n and construction and which is compact instructure and efficient in operation.

Another object of the invention is to provide a rotary pump suited to pump fluids including those in which solid particles are suspended. The novel construction of the working parts; especially the piston member, is such thatthe pump may operate at relatively high speeds with comparatively little wear or loss of efiiciency due to abrasion,

and thus possess a long life \in service without reference being had to the accompanying drawing forming a part of this specification wherein like reference characters designate corresponding partsin the several views.

In the drawing: a

the pump is particularly Referring to the drawing. the reference numeral Ill designates a drive shaft which is mounted for rotation within a suitable housing ll, preferably formedas a portion of the enclosed pump chamber housing IS. The shaft II is adapted to be rotatably driven by any suitable source of driving power (not shown). The housing H may be of any suitable size and construction and the shaft I0 is mounted for rotation therein in any desired operative manner such as by means of the bearing l2. The pump chamber housing [3 is enclosed by a removable plate or cover 14 which is held in fluid-tight engagement with a gasket I5 by any suitable fastening means such, for example, as the bolts and nuts l6.,

As best shown in Figs. 2, 3 and' 4, the pumping chamber in the housing I3 consistsof what in effect are two chambers l1 and I8 connected by an opening 19. The intake port 20 and the exhaust port 2I comm1micate with the chamber H. The pump assembly designated generally by the numeral 22 is'mounted in both the chambers I1 and I8 and extends through the communicating opening 19. The pump assembly 22 comprises an eccentric driving cam 30 which i keyed as at 3| to the end of the shaft Ill for rotation with said shaft. An annular body member 32 having an extending tongue 33 is pressed fit or other wise secured to the cam 30 for movement therewith. A covering 34 of resilient material is secured to the body member 32 and the tongue 33 and is so formed as to provide a resilient diaphragm 35 having an enlarged Peripheral bead 36 which is anchored in th housing l3 and serves to suspend the pump assembly 22 in the chambers l1 and I 8. The pump assembly 22 thus divides the chamber l1. into three portions indi- Fig. 1 is a side elevation in central longitu- Before explaining in detail the present invention it is to be understood that the invention is not limited in its application to the details of constructiont and arrangement of parts illustrated in the accompanying drawing, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

cated as lla, 11b and. He, respectively. The intake port 20 communicates with the chamber portion Na and the exhaust port 2| communicates with the chamber portion lJb. An air intake and exhaust port. 23 communicates with the chamber portion I10 and allows the chamber to be emptied or filled with air as required by movement of the resilient diaphragm 35.

A novel feature of the present invention is that the resilient layer 34 of the pum assembly 22 is provided with serrations about its periphery, as indicated by the numeral 40. These serrations preferably extend across the lateral face and are spaced circumferentially around the periphery adJacent the generally circularportion of the member 32. The resilient layer of the pump assembly is preferably provided with a smooth or unserrated portion immediately adjacent the sidewardly extending tongue portion 33 of the member 32. I1 desired, a shoulder portion, thickvide an effective seal when the pump assembly 22 is in the position there shown.

The operation of a pump embodying the novel improvements of the present invention will best be understood by reference to Figs. 2, 3 and 4 in which are shown the relative positions of the parts during various stages in one complete pumping cycle. In this description, it is as sumed that the direction of rotation of the shaft I0 is in a. counterclockwise direction.

Upon rotation of the shaft III in a counterclockwise direction the eccentric cam 30 connected theretois likewise rotated in the same direction and imparts an eccentric motion to the annular body member 32 surrounding it. When the parts are in the position shown in Fig. 4 the pump is at the beginning of its pumping cycle.

' In this position the intake port 20 and the exhaust port 2| both are closed by the enlarged serrations 40a and 40b. Fluid is entrapped in the space between the outer surface of the pump assembly 22 and the wall of the pumping chamber l8.- Upon rotation of the shaft III, the parts assume the position shown in Fig. 2 and the entrapped fluid in the chamber 18 is pushed before the progressing pump assembly 22 and is forced outthrough the exhaust port 2|.

In Fig. 3 the relative positions of the parts of the pump are shown in one stage of the pumping cycle. As there shown, the resilient covering of the pump assembly adjacent the high spot on the eccentric cam 30 is in fluid-tight contact with haust ports both are closed by the enlarged serrations llla and 40b, which in this position contact the wall of the chamber I 8. Due to this novel construction of the enlarged serrations a and 40b and the serrations 40 on the rotor assembly 20, fluid cannot by-pass the piston member. Since fluid is pumped through the fluid chamber by being forced ahead of the moving piston member, it is suckedthrough the intake port and forced out of the exhaust port 2|.

In view of the foregoing it will be understood that a pump embodying my novel improvements is self-priming. If desired, however, a system of check valves, held open by the constant flow of fluid through the pump, may be provided so that upon stopping of the pump assembly, the suction will be cut off and the check valves will close and fluid will be retained in the pump until the pump assembly is operated,

It will be seen that'the present construction of the serrated resilient member is particularly adapted to operate successfully in the pumping of fluids in which solid particles are suspended. Such serrations permit ready distortion of the resilient element and thus permit the passage of suspended solid particles between the surface of the chamber 13 and the pumping assembly 22. Also, the fluid trapped between adjacent serrations provides a fluid seal as well as a lubricant.

The serrations on the outer surface of the piston member also provide a relatively small surface area of contact between the resilient covering and the wall of the pumping chamber. This smallerqarea of contact decreases friction between the moving piston member and the wall of the pumping chamber. Asthe ends of-the serrations are depressed during movement of the pump assembly 22, as indicated, it will be seen that such depressing of the ends of the serrations prevents distortion of the entire resilient coating. The depression of a portion of the serrations offers much less resistance to movement thesurface of the wall of the chamber 13. As the rotation of the piston member continues, this point of contact progresses about the wall of the chamber l8 and the fluid is forced ahead of such moving point of contact toward the exhaust port 2|. At the same timeon the-opposite side of this point of contact, fluid is drawn into the chamber l8 through the intake port 20. As the movement of the parts continues the parts resume the positions shown in Fig. 4 which completes the pumping cycle. The movement of the eccentric cam and the member 32 is accommodated by distortion of the resilient diaphragm 35, as shown in Figs. 2, 3 and 4. The tongue 33 on the member 32 acts as a reinforcement for The resilient member and provides a rigid movable thandoes the entire resilient covering. Consequently, a piston member made in accordance with the present invention may be operated at higher speeds because less resistance is offered to it and, in addition, is much less subject to wear. It should be noted in particular that in the present invention each serration 43, after it has contacted the wall of the chamber Iii returns to its normal position before it again contacts that wall of the chamber. This is possible because only few of the serrations contact the wall at any given 1 time. Therefore, in the present invention the partition between the intake port 20 and the exhaust port 2| in the chamber I1.

' In view of the foregoing itwill be understood that due to the position and dimensions of the enlarged serrations 40a and 40b, the intake port "and the exhaust port 2| never communicate directly with eachpther. If both the intake and the exhaust portsare open, as shown in Fig. 3, the point opposite the high point of the eccentric cam 33 contacts the wall ofthe pumping chamber ID to cut off direct communication between the intake and exhaust ports. If this high point does not contact the wall of the pumping chamber, as shown in Fig. 4, the intake and exresilient covering is not more or less permanently distorted or strained as it would be if a flat surfaced coatirig were used. This feature, in addition to permitting operation of the pump assembly at relatively high speeds without damaging results, also increases the life of the covering: It has been found that the contact of relatively few of the serrations 40 with the wall of the chamber provides an efl'ective seal. between the pump assembly and the pumping chamber for pumping p p Iclaim:

l. A rotary pump, comprising a body having a pumping chamber provided with intake and exhaust ports, a revolvable eccentric member mounted in said chamber, a piston member having a series of closely spaced radially disposed flexible ribs extending throughout a major portion of its exterior circumferentialwall surface.

said ribs extending completely across such wall surface and'the ribs at each end of saidvseries beingotincreasedradialextent,saidpistonmemher being concentrically mounted on said eccentric member for eccentric motivation therewith .to provide throughouteach revolution oi the eccentric member a moving resilient contact between some oi the intermediate flexible ribs 01' the piston port.

2. A rotary pinnp, comprising a body portion having a pumping chamber and another body portion having a supplemental the two chambers being in communication and the last mentioned portion being provided with opposedintakeandexhaustportsiorsaidsuppleother predetermined times.

ase sss 1 mental chamber, a revolvabie eccentric member mounted in said pumping chamber, a piston memberhaving the major portion of its exterior circumterential wall surface provided with closely spaced radially extending flexible ribs transverse- 1y disposed with respect to such wall surface, said piston member being mounted on said eccentric member for eccentric motivation therewith to maintain a moving substantially fluidtight surface contact between saidpiston member ribs and the interior wall of said pumping aoportlonoithe chamber. said piston member having an arm extending radially therefrom into said supplemental chamber between said intake and exhaustports and connected to an intermediate portion of a flexible web having its ends anchored to the body portion or said supplemental chamber, said ports lying onthat side of said web which is toward said pumping chamber, and an air ventior that supplemental chamber which lies side of said web.

. on the opposite f CORNEIIUS .W. RANB'I'. 

